The issue had been troubling Jack Straw, and though he must have known that it might cause offence, he decided to raise it regardless.

One of Labour's most experienced politicians, Mr Straw addressed a gathering of Muslim leaders, sharing his disquiet over women who veiled their faces, and recalling a meeting he had had at a constituency surgery in Blackburn with a woman wearing a niqab.

It was a strange matter to raise at talks which had been dominated by a debate over Iraq's role in swelling British extremism, and his intervention stuck in the minds of those who were there. "He said, some of my constituents who have been accepting of the hijab are greatly concerned about the niqab," said one who was there. That discussion was almost 12 months ago. Mr Straw was warned at the time that any attempt to publicise his concerns would provoke anger. But a year later, and apparently unprompted by Downing Street, he chose to do so again, this time to the media.

If Mr Straw had any doubt over the news value of his views, editors at his local paper did not share them.

When the Lancashire Telegraph received his column on Wednesday morning, they knew straight away it was in a different league from his standard offerings. The front page for the next day was cleared and staff began approaching local community leaders to get their response.

Taking over the news

By yesterday morning, there was a gathering sense of crisis at Westminster and beyond over the government's attitude to multiculturalism, coming at the end of a week in which problems seemed to coalesce.

Anger over a Muslim police officer who asked to be excused guard duties at the Israeli embassy combined with tensions in Windsor, where plans to build a mosque sparked three nights of violent clashes, giving British Muslims a frustrating sense of once again being the whipping boy.

"This Muslim police officer taken off-duty was a routine thing, but it was blown totally out of proportion," said Dr Reefat Drabu of the Muslim Council of Britain. "The same with the niqab. It is a matter of choice but it seems to have taken over the news. We seem to be all the time defending ourselves and we haven't got the opportunity to evolve within the culture we're in."

It was the timing of the remarks, as much as the content, that was baffling Muslim leaders yesterday. Quietly, and unnoticed, the issue of the niqab has been raised on university campuses and in schools over the last few years, without causing ripples.

In the wake of 7/7, a dress code drawn up by Imperial College outlawed the niqab in the interests of security, saying staff had to be able to check students' faces against the picture on their ID.

The ban was resisted by the Imperial's Islamic Society, but has already been supported by at least one minister.

In a speech made at South Bank University in May, the higher education minister Bill Rammell said: "Many teachers would feel very uncomfortable about their ability to teach students who were covering their faces. And I doubt many students would feel it was acceptable to be taught by someone who had chosen to veil their face."

Shift since 7/7

A prominent academic agreed yesterday. Jean Seaton, professor of media history at the University of Westminster, said she would be reluctant to teach a student who covered their face. "You can't teach somebody if they can't communicate, without seeing the response. Teaching is not like stuffing a goose with corn - its utterly reactive. In a social situation, everybody else's faces are giving away stuff left right and centre."

Professor Seaton added: "I remember the first time I saw a Saudi in Holland Park and being viscerally terrified of this image."

But the government's perspective on relations with the Muslim and other ethnic minority communities appears to have shifted significantly since the London bombings. Its immediate reaction to 7/7 was to reach out to community representatives to discuss how the problems of extremism might be tackled.

But in August, Ruth Kelly, the communities secretary, called for a "new and honest debate" on the merits of multiculturalism. At last week's Labour conference the home secretary John Reid said Britain would not be bullied by Muslim fanatics, and he would not tolerate "no-go" neighbourhoods. The government has also appointed Trevor Phillips, head of the Commission for Racial Equality and a man who has warned that Britain is "sleepwalking towards segregation", as the chair of the new single equalities body.

Dr Drabu said attempts at rapprochement with Muslims were a "charade".

"They had these working groups, but when it came out that they would like an inquiry, that was totally ignored. When they said this was all to do with foreign policy, that was ignored."

It was not clear whether Mr Straw canvassed opinion within government before writing his column. He does not appear to have spoken to Tony Blair. The prime minister's official spokesperson said only: "He believes it is right that people should be able to have a discussion and express personal views on issues such as this."

Nor does he appear to have consulted members of the community in Blackburn. Lord Patel, a long-term supporter, said he would request a meeting to discuss the matter. Hamid Qureshi, chair of the Lancashire Council of Mosques, described it as "blatant Muslim bashing".

Shahid Malik, the MP for Dewsbury, said: "It's not so much about what he has said as the climate in which he has said it, in which Muslims - and non-Muslims - are getting tired of Muslim stories. The veil isn't the problem; the problem is that people are frightened of it - they've never spoken to someone with a veil. This cannot and must not be about blaming one group, but about saying, we have all got to take collective responsibility. "

The veil has been a lightning rod issue since Turkey banned headscarves as a rejection of Ottoman conservatism. In France, which has the biggest Muslim population in Europe, the 2004 ban on "conspicuous" religious symbols in schools was seen as a means of shielding the secular state from the perceived threat of Islamic fundamentalism. Feminists have opposed the veil as a symbol of patriarchy.

The niqab is a Gulf Arab tradition which has been adopted by young British Muslim women even when their traditional cultures do not prescribe it.

Talk in Blackburn

Ghulan Choudhari of Radio Ramadan Blackburn said that only a small minority of women in Blackburn wore the full veil, but numbers were growing. He said: "It's partly down to the increased interest in our religion, especially among young people. But I can see Jack's point about the veil making some people uneasy. To be honest, I get uneasy talking to people who are wearing sunglasses. I don't like not being able to see their eyes."

Talk in the town was linking the column to Mr Straw's possible ambition to be Labour deputy leader - or, conversely, to a theory that he was not planning to fight Blackburn again and had things to get off his chest.

Mr Straw's constituency party secretary Phil Riley said: "Jack always has a word with me in advance about what he'll be saying in the Telegraph and I know this subject's been on his mind for a while.

"The big worry here is that Blackburn is becoming a divided town. Either you stand by and watch that process, doing nothing, or you engage people in a debate about it. Jack's started a conversation. He and I have talked about it quite a bit in the last few months. I know he's worried about the number of Blackburn-born girls who are taking it up. As he says, in the context of cultural cohesion it's something which just doesn't help."

Muslim opinion on the streets was not unsympathetic to Mr Straw, but hardly anyone put other communities' feelings before the religious right - duty in the eyes of a sizeable minority - to wear the full veil. A self-employed electrician waiting for the end of lessons at St Nicholas and St John infant and junior school - which is overwhelmingly Asian - said that the roots of social division were much older than veil-wearing.

"It's all to do with the way we were treated in the Seventies - I was regularly chased along here when I was a kid by white lads. Other communities just didn't want to know about us - funny that they're all so interested now in things like veils. I was a soldier in the British Army for 11 years and I can tell you very clearly how I couldn't get anywhere because I wasn't white but brown."

Several other parents waiting to collect children said that an increase in wearing the veil followed much better-organised Islamic teaching locally. One mother wearing a headscarf and shalwar kameez, but not a full veil, said: "When our mums and dads came here, it was all work, work, work for them, no time to study and no mosques. Now we have lessons in English, Urdu and Arabic and women are learning what their religion really asks them to do."

Mounting tension

Tuesday British National party distributes leaflets with cartoon picture of Muhammad in south London

Wednesday David Cameron wants Muslim schools to ensure a quarter of their intake comes from other faiths. Confrontations between white and Muslim youths in Windsor

Friday Mr Straw defends his position and again urges women not to cover their face with the niqab

The view from Blackburn

Asma Mirza, 29, housewife

"I certainly don't agree with Jack Straw because my religion demands that I wear this I have taken the full veil for 16 years now and I am much more comfortable wearing it. It is a matter of modesty as well as religion. I hope that it will not put other people off. Once they talk to me and get to know me, I think that problem disappears."

Masood Rahi, owner of telecom shop

"I think Jack Straw is probably right, especially in these days when security matters so much. It's all very well for someone to have your photograph and a form with your details on. But what use is that if they can't glance at your face to check? People should be ready to discuss it and to read what he actually said, rather than the headlines which give a rather different impression."

Jahangir Hussain, 16,student

"I disagree with Straw. It's these women's religion. They should all be wearing the veil according to the proper teaching. Yes, maybe it puts some people off but look at nuns or people from other faiths which get people to do things with their clothes ... Nobody goes around telling them what they can and can't wear, they just get used to it."

Young woman in full veil. No name given

"OK, it's religion first but modesty comes into it a lot for me. I started using the full veil eight months ago and it's done so much for my self-respect. It's comfortable, I feel protected and I happily eat out at McDonald's in it. I've devised this special way of getting the food up behind the material."

Daniel Coine, 16, student

"I'd go further than Jack Straw and say they should all take off their veils. You need to see people face to face. It's weird not knowing who it is you're passing in the street, specially late at night when someone might jump you."

Rachael Ashhead, 20, business student at Manchester Metropolitan University

"It's their choice to wear the veil and they've an absolute right ... I've no problem with it all when I meet one - there are loads of them at uni. A more important issue is the way these things are discussed in the news, how they get simplified and people set against each other."